The present invention relates to an apparatus for testing an I/O interface of a computer system, and especially, to a test apparatus with capability of emulation of the real distance environment.
With respect to the testing of I/O interfaces in a computer system, a well-known loopback approach is utilized in general. The loopback approach is described as follows. In a function test of an I/O interface of a computer, a test apparatus is connected to the I/O interface of the computer. When the computer outputs a set of data via the I/O interface, the test apparatus receives and sends directly the set of data back to the I/O interface. The I/O interface then sends the set of data to the computer to determine whether the I/O interface works normally. If no difference between the output data and the return data is decided, the function of the I/O interface will be considered to meet the design requirement. In general, an I/O interface in a computer system, such as an infra-red (IR) interface, or a RS-232 interface, or a network interface, requires the function test as mentioned above.
However, according to the practical experiences, the I/O interface, which pass the function test by the loopback approach, may still malfunction under actual operation environment. The cause is the environment of the loopback approach cannot accurately reflect the I/O interface under the real distance condition. Therefore, a more conservative approach is to transmit signals to a test apparatus and then to send the signals back after a delay. The environment of the approach is much close to the I/O interface under the real distance condition.
The concept and spirit of this present invention are applicable to the function test of an IR interface, a RS-232 interface, and a network interface.
The invention provides an apparatus for testing an I/O interface in a computer system, e.g., an IR interface, or a RS-232 interface, or a network interface. The test apparatus is capable of testing the I/O interface under the real distance condition.
According to this invention, the test apparatus communicates with a first I/O interface in the computer system via a signal intermediary. The test apparatus includes a memory means, a clock generator for outputting a clock signal, an I/O interface communicating with the first I/O interface in the computer system via the signal medium, and a controller connected to the I/O interface. The controller synchronously operates with the clock signal. The clock signal drives the controller for writing data transmitted from the first I/O interface into the memory means, or reading out the data from the memory means and then transmitting to the first I/O interface through the I/O interface when a predetermined condition becomes effective.